Simple definition for SSL certificate

SSL certificates are small data files that digitally bind a cryptographic key to organization details.

What is the cryptographic key?

A cryptographic key is a string of bits used by a cryptographic algorithm to transform plain text into a cipher (secret) text or vice versa. This key remains private and ensures secure communication.

When we install an SSL certificate on a web server it activates the secure connection and uses HTTPS protocol in lieu of HTTP.

With SSL certificate we enable a secure connection between the browser and web server.